Several vehicle auxiliary lighting systems have been proposed. For instance, JP-7-186824A discloses a system provided with a bulb, a higher position irradiating outer lens and a lower position irradiating outer lens which output light, and a drive mirror. The drive mirror is positioned between the higher position irradiating outer lens and the bulb. When performing the higher position irradiation on a snowy road or the like, the drive mirror lowers and the light from the bulb is emitted from the higher position irradiating outer lens without being reflected by the drive mirror. On the other hand, when the lower position irradiation is performed in foggy conditions or the like, the drive mirror raises, and the light from the bulb is reflected by the drive mirror and emitted from the lower position irradiating outer lens.
In the device disclosed in JP-2001-351411A, a fixed shade and a movable shade are combined, and by moving the movable shade, a plurality of luminous intensity distribution patterns are generated. More specifically, when the movable shade is in a first position, a part of the light from a light source is blocked by an opening of the movable shade, and thus a luminous intensity distribution pattern for the foggy weather is irradiated. Alternatively, when the movable shade is in a second position, the luminous intensity distribution pattern for the foggy weather is irradiated.
Although conventional auxiliary lighting apparatuses disclosed in JP-7-186824A and JP-2001-351411A are capable of performing the luminous intensity distribution suitable to a case where there is the snow or the fog in the surroundings of a vehicle, they are incapable of turning on and controlling the luminous intensity distribution suitably in accordance with a degree (i.e., severity) of the weather condition. This can be problematic, for example, when the fog is thick, and a driver of a vehicle is distracted by the light irregularly reflected by the fog due to the optical axis of the light being excessively high. Similarly, when the fog is thin, the light is unable to reach a distant place on account of the optical axis being excessively low, which can impair the driver's vision of the road. Thus, the conventional auxiliary lighting apparatuses suffer from certain disadvantages that can detrimentally affect a driver's vision.